Positive printing in color photography



Jn.11,1944.A E, B. HESSER ETAL 2,338,849

POSITIVE PRINTING IN COLOR PHOTOGRAPHY Filed Aug. 29, 1938 2 sheets-sheet 1 Jan. 11, 1944. E; B 'HESSER TAL 2,338,849

POSITIVE PRINTING IN COLOR PHOTOGRAPHY Filed Aug. 29, 1958 2 sheets-sheet 2 [TQ-(L9 4 @la M @/za f e Ysglw Iva/275g ig wpa/Z Z Elan/mm W/z/ Image Blue Image Z4 Patented Jan. 11, 1944 POSITIVE PRINTING IN COLOR PHOTOGRAPHY Edwin Bower Hesser and Eva/Louise V. Hessel',

West Hollywood, Calif., assignors, by mesne assignmenis, to Edwin Bower Besser, a's trustee Application August 29, 1938, Serial No. 227,286

16 Claims. (Cl. 95-2) This invention relates to a new and improved method of making natural color photographs and particularly to a new and improved method of printing in color photography and cinematography.

One of the objects of this invention is to provide a new and improved method of making positive transparencies in color photography.

An additional object is to provide a new and improved methodfor producing color pictures in positive form from color separation negatives in a manner such that three positive images corresponding to different color sensations can be produced from two color separation negatives on double coated positive stock.

A further object is the provision of new and improved types of positive stock for making positive transparencies from color separation negatives.

' Another object is the provision of a new and improved method of incorporating a black key image into positive transparencies containing two or more colored images/in two emulsion layers carried on asingle support.

Still further objects of the invention are the provision of newand improved negative material particularly adapted for positive printing by procedures outlined herein.

Another object is the provision of new and improved methods of processing negative materials which, when used in conjunction with our new and improved methods of printing. provide simplified over-al1 procedures for making color photographs.

Still a further object of the invention is to prointermediate between said developed images by printing through one or both of the developed images, preferably the uncolored developed image, to form a latent image, then developing said 1atent image and coloring the uncolored images according to their appropriate color printing values.

The negatives which are used to form positive prints in the manner just described may be prey pared in any suitable manner eitherby takinga picture on negative nlm containing' two or more superposed emulsions of different color selective sensitivities on the same support; or two or more superposed emulsions of different color selectivip p larly desirable to photograph the object on a new vide new and improved simplified methods of incorporating a sound track into positive transparencies for motion picture projection.,

One of'the further objects of the invention is to provide a method for producing a sound track on motion picture film which is superior in reproducing qualities to sound tracks at present ,said images in its appropriate color value on one side o'f said support only and forming an image and improved type of bi-pack material which is especially designed to simplify positive printing in the manner more fully hereinafter described. 'I'his bi-pack material has a front element which is green sensation recording and a rear element which is red sensation recording. The preferred arrangement in the order nearest the camera lens during exposure comprises a front element having an overlying yellow filter layer made of gelatin or the like, a transparent support carrying said yellow lter layer, an'orthochromatic silver halide emulsion normally recording blue and green 'sensations but not red on the reverse side of said transparent support, a red filter layer over said orthochromatic emulsion and adapted to be placed in contact with the' second element which comprises a panchromatlc emulsion carried on a transparent support, said transparent support preferably having an anti-halation layerl on the one emulsion layer on each side thereof, developing said images to silver images, coloring one of which records blue, or as it is commonly called blue-green, on the front element and red on the rear element. Such a. bi-pack is sold today under the name of Du-Pak. It is to be noted graphed on a tri-pack, that is a, lm consisting of three supports. one carrying a blue sensitive emulsion, another a green sensitive emulsion and the third a red sensitive emulsion, the blue sensation 'recording emulsion is proper for printing in yellow, the green sensation recording emulsion is proper for printing in magenta, and the red sensation recordingemulsion is proper .for printingin blue.

In carrying out this invention we have found thatit is possible to produce a positive having three color printing values on positive printing stock containing only one emulsion layer on each side thereof. In other words, by our method we can take ordinary double coated printing stock such as is used in two color photography and produce three color prints therefrom. Additionally, from double coated stock of the type described we can produce positive prints containing two or three colors as well as a black key print. One of the features of our invention lies in the fact that according to a preferred embodiment of the invention, yellow,` which is least important in value, is recorded intermediately between blue and magenta on positive printing stock containing only one emulsion on each side thereof. That is to say, blue and magenta are recorded on those portions of each emulsion near the exterior thereof while yellow is recorded on one of said emulsions, preferably the emulsion colored'blue in the interior thereof adjacent the transparent support. Similarly, a black key image may be recorded adjacent the transparent support or y yellow can be recorded on one side of said support and a black key image on the other side.

In printing, according to the methods herein described, we also preferably employ a new and improved type of positive nlm in which the emultion the condition or state of the positive printing stock at intermediate stages during the printing operation;

Figures 7, 8, 9 and l0 represent partly in crosssection various forms of positives which may be prepared in accordance with the invention;

Figure 11 is a plan View of motion picture Astock showing the position of the sound track and the pictorial images;

Figure 12 is a cross-sectional view of the printing stock shown in Figure ll printed and developed in accordance with the present invention with a sound track in green;

Figure 13 is a cross-sectional view of another improved form of positive printing stock; and

Figure 14 represents generally a film of this type after it has been printed according to one the yellow filter layer should preferably have a sion coated on one side of transparent support is Y -substantially thicker than that coated on the Other features and advantages of the invention J will be apparent by reference to the following description in conjunction with the accompanying drawings, in which:

Figure 1 represents partly in cross-section a l preferred type of bi-pack illm to be employed in photographing an object; Y

Figure 2 represents partly in cross-section 4the ordinary type of positive printing stock such asis now used in two color printing:

strength between K-l and K-2 Wrattan lter color standard, that is, of the definite ability to so screen the entrant light that the emulsion 6 is green sensation recording in its part-negative production value. .The yellow dye used may be any suitable type of yellow dye which washes The panchromatic emulsion i2 may be prepared I in any suitable manner such as is well known in the art.

Water-soluble l through the front element-*of transparent support 2 causes the orthochromatic emulsion 6, which would ordinarily be substantially blue sensation recording, to b'e now green sensation recording by its action in removing the blue light. Thus, emulsion 6 records green sensations, leaving magenta. color areas' transparent and yellow representing areas relatively veiled or opaque.

A somewhat similar effect can be obtained by i camera. For true rendition, however, we prefer .to have the yellow lter associated with the front element as just described.

Figure 3 represents partly in cross-section an l improved type of printing stock in which one of the emulsions on one side thereof is substantial! thicker than that on the other side;

Figure 4 represents partly in cross-section still another new and improved type oi.' printing stock `provided in accordance withthe present invention:

Figures 5 and 6 represent partly in cross-sec- In Figure 2, the transparent support I0 carries on opposite sides thereof positive emulsions I8 and 20 which maybe prepared in any suitable manner suchas is well known in the art. I

Positive printing stock of this type is available under the trade name Duplicoat." In such printing stock, one or both of the emulsions ordinarily contain a' yellow restrainingl dye which washes out in development.

' In Figure 3, the transparent support Il carries positive emulsions i8' and 20', which emulsions may be similar to those described in conjunc- The rear element,

yellowl lter layer 4 acting orthochromatic emulsion sensitive to blue andi green but insensitive to red. On the opposite side of the support, emulsion 24 is of the ordinary positive type, that is, insensitive to red light.

As illustrated in Figures 11 and 1,2, the invention is especially suited for making positive transparencies for motion picture projection. Figure 1l is a plan view of positive motion picture stock showing pictorial image areas 30, sound track 32, guide holes 34 and 36 and marginal areas 38 and 40. Figure 12 is a. view partly in cross-section showing a preferred form of our invention in which the sound track is green as a result of a combination of yellow and blue in regions C and E, respectively of emulsion layer I8.

The other gures of the drawings will be better understood by reference to the following examples in which preferred embodiments of the invention are described:

' Example I onto the surface of emulsion I8, herein referred to as the reverse side of the stock. This printing on the surfaces of the emulsion, or the parts of the emulsions adjacent the surfaces thereof,

may be accomplished simultaneously in a double printing cinemagraphic printer, the positive l stock being sandwiched between the two negatives. The depth of printing can be regulated by intensity of the printing light, the time of exposure and the density of the negative., With a light printing, latent images may be formed in those portions of emulsions I8 and 20 4of Figure 5 adjacent the surfaces thereof, while leaving sensitive emulsion in each of said emulsions adjacent the transparent support I8.

These simultaneously printed latent images are developed simultaneously by a surface'development which requires about two minutes. This development is a well known type of operation and the developer used is preferably a metol-hydroquinone developer of the type which converts the latent images A and E into silver metallic images.

Following development, the positive is placedA into a water bath which washes out the developer, but at this time there is no fixation of the film,

that is, removal of undeveloped emulsion as is common in two-color printing on double coated positive film of the type which we have illustrated.

The next step consists in applying an iron blue toner such as a combination of iron and ammonium citrate in solution with potassium ferricyanide and a weak acid to the side of the double coated positive stock indicated by E in Figure 5.

, A suitable blue toning solution is as follows:

the course of development the yellow filter layer v y ing solution, leaving a pure green sensation recording negative originally the front element,

and a red sensation recording negative originally the rear element.

We have discovered that when a green sensation recording negative is normally, that is, lightly but suitably printed onto a, positive photographic material, the portions of the scene dep1' cted which represent yellowl print in the positive as white, but that when the same negative is printed to a much greater degree, the portion representing yelldw7 will become darker in relation to the amount of light used in printing. This phenomenon is readily demonstrable in a Cinex or light testing strip of motion picture film. Taking as an example a color test chart in which one yellow surface is plainly marked Y it should be observed that frames which have been printed light show little silver deposit, lbut darker printed frames show denite silver deposit. Accordingly, we have found that this deeper. printing-of the green sensation negative to show yellow may be impressed upon a positive emulsion underlying an already formed positive print of lighter nature made from the same green sensation negative. In order to accomplish this we preferably proceed as follows:

. Assuming-that .we are using the positive stock illustrated in Figure 2,. wek print through the green sensation negative onto emulsion 20 which is herein referred to as the obverse side of the Figure 5 by notation, or any other suitable means,

Potassium ferricyanide grams 5 Ferrie ammonium citrate do 20 Oxalic acid do 10 Hydrochloric acid cc 25 Water m cc 4,000

The action of the -iron toning solution is confined to the area indicated -by E in Figure 5, which has already been changed into a black metallic silver image by development and which is now changed into a blue ferrie image. This application may be attained -by flotation or by known means of mechanical application such as rollers. At this point the positive stock has the general cross-sectional appearance illustrated by Figure 5. In other words, the'obverse side of the stock or emulsion 20 contains near its surface a silver image which is uncolored but eventually is to be colored magenta. Beneath ,said silver image is a sensitive emulsion area B because all of the steps thus far have been conducted in the dark or in light which will not expose the unprinted emulsion. On the reverse side 0f the support, emulsion I8 contains a sensitive area C and area E has been toned blue.

At this point we preferably fix emulsion 20 of thus clearing region B without affecting region C. After xing emulsion 20, we print from the green negative a second time through-silver image A but with a stronger printing light and a length pass through not only the negative but the positive silver image already formed in A which is not transparent. Thus, in regions depicting white the negative itself is opaque and the already formed silver image in A is also opaque, and obviously no impression will be created by this printing operation upon the light sensitive underlying region C in emulsion I8. However, in the regions of the image formed in A in the firstprinting, which in the object photographed werel yellow, transparency exists due to the opacity of the green sensation printing negative. When the second printing operation occurs, no opposition is. encountered to the passing of light rays through A in these yellow representing regions to the underlying light sensitive region in emulsion I8.v

`Following the second printing operation the latent image formed is developed by a second developer of such character that it has no eiect on the blue toned image in area E. For this purpose a developer of the amidol, sodium sulte and potassium bromide type is preferred.' A typical formula of such a developer is as follows:

The iilm is then fixed out with a solution of sodium thiosulfate. A typical xing solution is:

Sodium `thiosuliate g'rams-- 1,000 Water to cr' 4,000

The lm as a. whole may now be bleached so that the silver images at A intended for magneta -coloring and at C, intended for yellow coloring,

may be converted intov silver iodide capable of mordanting basic dyes. A typical mordanting solution for this purpose has the following coml position:

Potassium iodide 'grams 60 Iodine l dn 10 Potassium ferricyanide --do 60 Acetic acid cc-- 60 Water tomake cc- 4,000

Example II In this examplethe following steps are employed in printing athree-color positive from two negatives obtained by photographing an object with abi-pack such as described in Figure 1:

1. The green sensation negative and the red I sensation vnegative-are simultaneously printed from opposite sides onto positive printing stock of the type described in Figure 2, the green sensation negative being printed in the outer portion of emulsion layer 20 and the red sensation negative in the outer portion of-emulsion layer I8.

2. The latent images formed by the printing a metal-hydroquinone developer, vthus forming developed silver images in regions A and E of Figure 5.

3. The nlm is washed without lining. 4. The image in region E is blue toned by ilotation in the manner described in Example I. i

-5. The image in region A of emulsion 20 is red toned by treatment with a uranium nitrate solu- I developed in an amidol type ofdeveloper `such as' Sodium sull-ite grams 90 to 180 Sodium bisulte do 20 to 50 Amidol rin 15 to 45 VPotassium bromide do 3 to l0 Water to cr- 4,000

tion. Such a. solution may have the following composition:

sation negative is then printed through region A. '7. The latent image formed in region B is described in Example I.

8. The entire iilm is xed clearing any'undeveloyed portions. Y

9. The entire emulsion 20 is bleached by iiotation or similar application of an iodine bath such as described in Example I.

l0. Region A of emulsion 20 is briefly immersed in a strong magenta basic dye solution.

11. Emulsion 20 is washed.

l2. Emulsion 20 is immersed in a very weak yellow basic dye solution which slowly mordants into the region bleached only with iodine. Thus a three color positive is formed having a mordanted magenta image in region A of Figure 5, a-mordanted yellow image in region B and a blue toned silver image in region E.

Example III l -The procedures of ExamplesI I and III can be tive for the second printing. This blue sensation recording negative may be prepared in any convenient manner, for example, by photographing,

Y the object with a tri-pack film and preparing `three color'separation negatives therefrom, or by photographing the object 'ion three different emulsion layers, carried on separate supports, using beam splitting devices in order to form geometrically identical vlatent images in each emulsion. Alternatively, three negatives comprising a blue sensation recording negative for printing l 'in yellow, a green sensation recording negative for printing in magenta and a. red sensation recording negative for printing in blue may be 'formed by photographing the object on 'a iilm containing two or more emulsions of different sensitivities on a single support and then copying to form color separation negatives.-

Regardless of the manner in which the color separationvnegatives are obtained, the method of positive printing employed in Examples I and II may be employed, the red sensation recording negative being used to form a silver image in region E, the green sensation negative being used operation in Step 1 areboth simultaneously developed in an ordinary type of developer such as to form an image for magenta coloring in region A and the blue sensation negative being used to form an image for yellow coloring either in region B or region C, or both.

v Example IV negative on emulsions 20 and I8, of the positive stock, thus forming latent images in regions A and E'.

Following the printing operation, both of said latent images are developed in an ordinary type of developer, as, for example, a metolhydroquinone developer which converts the latent images in A and E' into silver metallic images.

Development for about two minutes produces lightly formed surface images. The nature of the exposure in the printing operation issuch that a light normal development, as, for instance, a two minute development, will produce a silver image, as shown in E', while a much more prolonged development, as, for instance, six minutes, will increase the physical depth of the silver image produced in a manner indicated by the formation D. The depth of printing, that is, the amount of light penetrating the .negatives to the positive double coated stock, is within the con' trol of the operator of the double printing machine and is balanced to obtain correct printing densities. For the purpose of the present invention, the print from the red sensitive negative is made deeper than that from the-blue-green (or green) sensitivity negative. Thus, the latent image formed in emulsion I8 is actually much deeper than can be developed by the light two minute development in the metolhydroquinone developer.

Following development, thepositive is immediately placed in, a water bath which washes out the 'developer but at this period Athere is no fixation of the lm.

The next step consists in applying an iron blue toner such as acombination of iron and ammo'- nium citrate in solution with potassium ferricyanide and a weak acid, as illustrated in Example I, to one side of the double coated positive bearing emulsion I8 without touching the other side which bears emulsion 20 intended for red or magenta coloration. The action of the iron toning solution is confined'to the area indicated by E of Figure 6, which has already been changed into a black metallic silver image by development and which is now changed to a blue ferrie image. This application, as previously indicated, may be attained by flotation or any other suitable method.

Following this blue toning process, emulsion I8, already blue toned in the region indicated by E', is again developed so that an additional black silver image is formed in the region D' in which a latent image has been formed in the rst printing operation but which, owing to the prior two minute development being but partial in depth-forming characteristics, is not metallicized until the second development. 'I'he developer employed for the second development is preferably an amidol type of developer such as described in Example I which does not damage the blue toning already formed in region E.

After the second developing operation, emulsion IB contains both a blue toned image and a black metallic silver image, while emulsion 20 contains a black metallic silver image. The entire film is then fixed with a solution of sodium thiosulfate which will clear the unused, undeveloped e'mulsion.

Region A is then treated with a mordanting solution such as, for example, an iodiding mordant of the type described in Example I and mordant dyed with a magenta basic dye. Alternatively, region A' may be colored in a reddish or magenta color by toning in any suitable mauthrough the toned silver image of region A.

ner, as, for instance, by treatment with uranium nitrate in combination with potassium ferricyanide. The resultant positive obtained after suitably washing` and drying contains a black and white image in a buried or intermediate layer D', a blue toned silver image in region E' and a magenta colored image in region A.

Example V This example is given to illustrate the preparation of a positive transparency containing/three color part images of different color values and a black key image. As stated in Example IV, we have found that such a transparency can be obtained from twol color separation negatives, one of which'is a red sensation recording negative and the other of which is a green sensation recording negative or a blue-green sensation recording negative. Additionally, we have found that a positive transparency containing three color values and a black key image may be prepared upon ordinary positive stock of the type illustratedin Figure 2. This is accomplished in the following manner:

Positive stock of the type illustrated in Figure 2 is printed simultaneously in a sandwich type of contact printing machine, as, for instance, a Hughes cinematographic printer, the red sensation recording negative being printed onto emulsion I8 and the green (or blue-green) sensation recording negative being printed onto emulsion 20. In this manner a latent image is formed in region E' of Figure 6 for coloring in blue and another latent image is formed in region A' for coloring in magenta. These images are developed simultaneously by treatment with an ordinary type of developer', as, for instance, a metolhydroquinone developer, to form positive silver images.' The printing and development are such that there is a surface development at A' and E' leaving a latent underlying image at D in emulsion I8, an unsensitized emulsion at B' in emulsion 20. The .latent image in region D' may extend all the Way to support I6 or there may also be sensitive emulsion left inregion C' of emulsion i8.

Region E is then blue toned'with an iron tonerA of the type described in Example I, this being accomplished by flotation or in some other suitable manner such that region A' is not affected. Region A is then red toned by treatment with a uranium nitrate toning solution such as described in Example l1.

After toning in the manner described, the latent`image in region D' is developed in an amidol type of developer by flotation of layer I3 which does not affect the blue toned silver image, thus producing a black and white image underlying the blue toned silver image in emulsion I8. Another latent image is then formed in region B of emulsion 2li which Still contains sensitive emulsion, this being accomplished by printing If any undeveloped emulsion is left in region C'. latent images may be formed in both regions B' and C. This second printing is effected either with a blue-green negative such as may be ob tained from an ordinary bi-pack, or with a green sensation recording negative such as obtained from our special type of bi-pack described in Figure l, or with a blue sensation recording negative.

The latent image thus formed is then developed by an amidol 'type of developer. If desired, instead of developing the image in D' before the not treated with a uranium tone.

second printing, the image in D' may be developed simultaneously with the latent image in B'.

Following this development, the positive nlm contains four images, one in region A', which is a red toned silver image intended for magenta. coloration eventually, another in region E', which is already blue toned, and two underlying or intermediate images, one in regionB' (or in B and C') intended eventually-for yellow coloration and the other a black key imagein region D'.-

The emulsion layer 20 is then immersed by iiotation in an iodiding mordant of the type described in Example I. Thereafter region A' is dyed with `a basic magenta dye by a very brief flotation immersion in a strong magenta basic dye solution, followed by washing with water, which forms a vivid magenta color in the A' region which has been uranium toned, the magenta mordanting quickly and effectively to that region but washing out to a very great degree in the region B which was bleached with an iodine bleach but It should be understood that whereas these two regions were originally in diierent strata, the xing out process has brought the two regions into intermingling association, the differentiation existing at this point being solely between the individual silver grains, some of which havebeen treated with uranium toning, representing the magenta portion of the picture, and others withiodine bleach only, representing the yellow regions. Then the emulsion 20 is immersed in a very weakly yellow basic dye solution which slowly mordants into the region bleached only with iodine, that is to say, the B region. Thus, a four-color picture is formed with magenta coloration in region A', yellow coloration in region B (or B and C') blue coloration in region E' and a black key print in region D' Example VI Another valuable variation of our method of printing from bi-pack negatives is as lfollows: As in the previous examples, latent images are formed by printing according to any known method on two light sensitive emulsions I8 and 20 of Figure 2 upon opposite sides of support IE. Thus, from a blue-green sensation recording negatlve a positive latent image is formed on the surface region A' of emulsion 2 0 and from a red sensation recording negative a positive latent image is formed in the surface region E' of emulsion I8. The printing light used for printing from the blue-green sensation negative upon emulsion 20 is of such intensity that the image formed in A will be sufliciently strong in a two minute development in metolhydroquinone developer that it will be satisfactory without further development for conversion into a proper red or magenta dyed image formed in subsequent steps of the process.

The latent image formed in emulsion I8 from the red sensation recording negative should be sufficiently strong so that the two minute first development does not completely develop it to its full depth but only the area E' is developed. Then by flotational or other methods of application a blue toning solution is applied to emulsion I8, turning the silver image in region E' into a blue image without affecting emulsion 20 on the other side of support I8. Thereafter, without notation or other application with a, solution of sodium thiosulfate which removes the unused, undeveloped light sensitive emulsion represented by the region B' between image A' and support underlying the already blue toned surface image E' in emulsion I8 undeveloped unused but water washed light sensitive silver emulsion which is treatment in metolhydroquinone developer.

Another printing operation from the blue-green sensation negative is made through region A without having any eiect on the image because ity isl fully developed and fixed. This printing forms a latent image in region C' of emulsion I8 which mingles with the not yet developed deep latent image from the first printing remaining in region D of emulsion I8. Thus, anew image composed of the deepest printing from the red sensitive negative and a further image derived from a second printing of the blue-green sensitive negative somewhat sheltered by the density of the already formed black silver image in region A of emulsion 20 is formed in combined regions C' and D' of emulsion I8. This image is developed by treating the lm in a, second development with an amidol type of developer which does not injure the blue toned image in region E of emulsion It. Region A and region C', D are then subjected to a potassium iodide-iodine bleaching treatment which forms a highly satisfactory mordant for coloring by dyeing with basic dyes. Region A is dyed -with a basic magenta dye by flotation from one side of the support and region C', D' is dyed with a basic yellow dye from the other side of the support. We have found that the combination of printings from red sensation and blue-green sensation negatives in regions C and D of emulsion I8 when colored yellow in positive form is an excellent substitute for a proper negative exactly correct for yellow printing. The resultant positive transparency is, therefore, colored appropriately in three color values.

Example VII The following method is a variation of our process where three differing color separation negatives are available. This method is designed to g transfer these three color sensation recordings image in region A', as illustrated in Figure 6.

r'T0 aiecting emulsion I8, emulsion 20 is treated by Inasmuch as most optical printers are as definitely controllable in printing light penetration as contact printers, the printing light so used will be so regulated that the gamma of the latent image formed in A is correct for the representation of a final magenta coloration. The positive iilm is then turned over and printed upon the opposite side, that is, upon emulsion I8, using a red recording negative to intercept the source of printing light in the optical printer so that the latent image formed in this printing operation will correctly represent the positive image designed for blue coloration.

Following these two printlngs upon the obverse and reverse sides of the double coated positive, the 111m is developed in the ordinary tphotographic manner, changing latent images at A' of emulsion and E of emulsion' I8 Vinto silver images. Following this development a stop bath may be used which will arrest further development of either of the images and yet which will not affect or hinder the further usage ofthe underlying. undeveloped, unused light sensitive silver halideemulsions in region B of emulsion 20 and region C' of emulsion I8. Alternately, the printing light may be so controlled that every vistage of the latent image will be developed without necessitating the use of a stop bath.

Following development', the film is washed in the dark, after which it is floated on the side of obverse emulsion 20 in a solution ofsodium thiosulfate which has the effect of fixing out and clearing the undeveloped emulsion in region B behind orunderlying the silver image formed in A', thus leaving no sensitive material on the side of the transparent support I6 occupied by emulsion 20. Such fixation provides transparency in the parts not covered by an image in metallic silver, as depicted in region A.

Printing from the third negative, that is, the blue sensation recording proper for positive coloration in yellow is now effected by registrational light through this negative and the already formed silver image at A upon the underlying, unused photographically sensitive material in region C' of emulsion I8. According to our invention, a fourth printing, which is in reality a second printing from the blue sensation recording negative (yellow printer), is now made through the already blue toned positive image at 'The light rays are of course interrupted to a certain extent by the -opacity of the image in region E', yet penetrate the portions which are relatively transparent and which are exactly those needed for yellow representation since these transparent portions in the blue image, that is where the blueimage is absent,.

are the portions of the scene which represent the warmer portions 'of the picture, namely, the yellow and red portions. Thus, by printing through the black silver image A and blue toned silver image E', suilicient transparency is found to irnpress the full needed light necessary to aiiect emulsion C inthe underlying portion of emulsion I8 so that a latent image may be correctly formed therein to represent the yellowv phases or parts of the scene. Thus, in only two developing operations and without any resensitization whatsoever a blue positive image has been formed at E', while'a silver image at C,'representing the yellow, is formed by a second development, preferably in an amidol type of developer which will not ruin the blue toned image at E of ein1 sion I8.

The film as a whole may now be bleached so that the silver ima-ges at A' and at C' are converted into silver iodide capable of mordanting basic dyes, this being accomplished by treatment with an iodiding bath of the type previously described, then by ilotation or other mechanical means the image at A is mordant dyed magenta without affecting -the image at C', after which Example VIII In the foregoing examples the operations described may be eiected by using the positive stock illustrated in Figure 3 instead of that illustrated in Figure 2. In the positive stock illustrated in Figure 3. emulsion I8' corresponds to emulsion I 8 of Figure 2, and emulsion 20 to emulsion 20 of Figure 2. Each of these emulsions may be impregnated with a light restraining dye such as tartrazine in a manner well known in the Since this type of positive stock gives more depth in the emulsion in which we prefer to form a pluralityof images, it possesses marked advantages over the positive stool: described in Figure- 2.

a magenta colored image is formed in emulsion i 20. a blue toned image adjacent the surface of emulsion I8', and a yellow colored image in emulsion IB' adjacent support I6', this being accomplished according to the general procedure previously described.

Example IX This example is given to describe another variation of our printing process involving the use of another new and improved type of printing stock, as illustrated in Figure 4.

As previously described, the printing stock shown in Figure 4 comprises a transparent support 22 on the obverse side of which two emulsions are coated, that adjacent the support being a panchromatic emulsion 2li-which is overcoated with an orthochromatic emulsion 28 insensitive tored light. The reverse of the film bears one emulsion of ordinary positive type, insensitive to red light. This material is exceedingly valuable in printing from negatives diierent in image placement positionally from theusual bi-pack arrangement, as, for instance, when in .photographing where multiple images are produced.

side by side on one side of an emulsion, or when a, negative strip bearing images of diilerent selective sensitivities in succession is employed.

Region 26 being. sensitive to red light may be printed from any sensitivity negative desired by such light without in any away aiecting surface emulsion 28 through which the light properly adjusted as to strength and red filtration passes harmlessly. Ina preferred form of this invention the red sensation negative (blue printer) is used to impress upon emulsion 26 a latent image simultaneously with the' formation of an image developing said image on that side of the film by anl amidol developer. After this printing and development the film is xed. The iixation mentioned in relation to emulsion 24 may be postponed until this time if desired, the development of the image in emulsion 28 being accomplished preferably by otation. Thus, in emulsion 28, a silver image exists proper for magenta coloration. In emulsion 26 the image has already been toned its iinal color blue while in emulsion 24 there is -another silver image adapted for yellow coloration. Submersion of the entire lm in an iodine potassium iodid bleach is followed by a bi-suliite type eliminator of the iodine stain which prepares the silver images for color mordanting.

. which is still light sensitive.

The image in emulsion 28 is then dyed with a basic magenta dye by flotation or any other selective meansof association, and the image in emulsion 24 is similarly dyed with la basic yellow dye, thus making a three color positive transparency.

The so-und track may be printed with white light to impress a dual image on both emulsions 26 and 28, or it may be printed with red light upon emulsion 26 alone. In the former instance the sound track will be a combination of red and blue, in the latter blue alone. The addition 'of red to blue in the sound track tends to greater strength and finer reproduction qualities of sound tone than a transparent blue track alone.

. Example' X This example is given to describe a neW and improved method of copying as a step in the preparation of positive transparency where a photograph is originally taken on negative mate-l ria'l containing two or more emulsions of different photographing the object is developed in the ordinary photographic manner so that two silver images representing recordings in different portions of the spectrum are both developed. The

entire film was then immersed in a solution con-v taining chemicals capablev of toning the silver to either a brownish-red color or blue. 'For brownish-red toning this would be a solution containing uranium nitrate and potassium ferricyanide as the main ingredients. For blue toning We use a solution containing iron and ammonium citrateand potassium ferricyanide as the principal ingredients. However, any of many commercially known iron toning or uranium toning formulas can be used. 1

AS an example, the film is immersed in a brownish-red toner which changes each ofthe two superposed silver images into brownish-red images separated by undeveloped silver bromide To render this undeveloped emulsion insensitive to light without bodily removal s ch as immersion in a hypo 'solution would e ect, we have discovered that immersion in a solution containing iodine, potassium iodide and acetic acid results in conversion of such unexposed, undeveloped emulsion to a complex salt insensible to further development and providing a clear white background against which the images stand out clearly.

' of yellow, determined to the proper degree of support, which is of transparent nature, the. image can be clearly seen and photographically copied against the white background formed by iodiding the unexposed emulsion.

In another application of the same principle, an iron toning solution is substituted for the uranium nitrate toner. Thus, each' of the two images is turned blue by the conversion of the initial simple black silverimage to a blue image of iron ferrocyanide. vThe film is immersed in the solution of iodine and potassium iodide in the presence of a mild acid, converting the residual undeveloped light sensitive silver emulsion into a light, insensitive, clear white compound against which the blue images stand out prominently. The copying of thesetwo images onto separate supports, is carried out in the following manner: 'I'he complex compound formed from the unexposed light sensitive emulsion is because of its silver iodide content capable to a high degree of mordanting basic dyes, while the blue iron image is mordant resisting by nature. Thus, immersion in a solution containing a basic yellow dye, such as auramine or thioiiavine, will result f in the coloration of the background to a denite yellow color, leaving the images in blue. Thus, viewing they entire lm or plate from the side nearest; the lens during exposure, We will see the negative representation of the selective sensitivity which in manufacture was designed for recording a particular color phase and viewing from the back we see another negative image representing the differing color phase of the emulsion which in the act of photographic exposure was farthest from the lens; each of these images being blue in color against a background 'simple photography from the front of the film,

i. e., the side arranged nearest the proximity of the lens during exposure, a positive image is obtained which reflects, in positive form, the sensitivity of the negative film coated upon this We have. further discovered that the use of l uranium nitrate solution for brownish-red toning of negatives has an additional effect of so intensifying the image farthest from the lens during exposure as to cause it to come to the surface of the emulsion farthest from the lens. Thus, if

emulsion. Photographing similarly from the ,rear a positive image results which comprises the differing color selective sensitivity of the underlying emulsion, i. e., that farthest from the lens during exposure.

Color separation negatives prepared in lthis y manner maybe used in making positives according to the methods of any of the previous examples.

Example XI Another method .of copying which We have found very effective in the case of superposed emulsions when it is desired to retain transparency of the film for copying by transmitted light, as an ordinary negative, is as follows:

The negative material consistingof multiple superimposed emulsions of diiering color selective sensitivities is developed in the ordinary manner, washed and thenpplunged into either an uranium toning solution or an iron toning solution.. As an example, let us presume that the immersion is in an uranium toning solution, turning both images brown. By means-of length of immersion, the intensification of these images may be controlled at the will of the operator.

Following this toning, the entire 111m is immersed in a bath containing mainly sodium thiosulfate, which will not only removel the unexposed residual emulsion, but will render the two images, both in brown, more or less transparent. Viewed as a pair by reflected light, the two images seem as one, and jointly reflect the combined qualities of the two negative emulsions of differing selective sensitivities and are thus immediate-l ly capable of usage for any purpose requiring such dual sensitivities in combination, as for in.

stance, if the sensitivities were green and red, of complementary type, the pair would be eminently suitable for key printing, that is, as a shadow sensation recording.

After the key printing qualities are utilized by copying in known manner, the strata nearest the surface may be conveniently changed to blue coloration by quick surface treatment with a combination of iron, ammonium and potassium ferricyanide, so that such surface negative image is changed to blue, offering little'resistance to the passage of light rays to a light sensitive photographic material of panchromatic nature; the

*underlying brown uranium toned image oiering such resistance that it is readily copied by transmitted light. Following this copying operation, permitting preservation of the image nearest the support without such copying being affected by the blue image above it, this uranium toned image is readily removed by aconcentration of sodium thiosulfate which does not affect the brilliance of the blue image above it, or by other solutions in which uranium nitrate-formed images may be reduced to transparency, as for instance, by immersion in a photographie developer which does not affect the blue image, such as amidol and sodium sulfite with bi-sulte, but which discolors and renders a uranium toned image quickly transparent. The surviving blue image is readily copied on blue sensitive photographic material. Our improvement has obvious advantages, in copying, over methods which employ such materials as farmers reducer to etch away emulsions or other etching operations employing hot water to soften gelatine.

Original or duplicated negatives prepared in this manner may be used directly in making positive transparencies, according to our methods of procedure.

Example XII This example is a variation of Example V. vThe film used is the double coated positive fllm of commerce, as illustrated in Figure 2, or our preferred type of positive shown in Figure 3. A printing operation exposes the surface region A of emulsion 20 (Fig. 5) from themagenta printer negativeysimultaneously or consecutively with- Cc. Water 4,000 Glacial acetic acid 60 This in turn is followedl by thorough washing. partial drying by air squeegee, and treatment of the rear emulsion, i8, by flotation on a blue tnfying solution similar to that used in Example I.

and selective treatment of the front emulsion 20, by flotation or any other convenient method. with a solution capable of uranium toning, e. g.. one containing:

, i Cc.' Uranium Anitrate 15 Oxalic acid 5 Potassium ferricyanide ".L-- 5 which turns the surface region silver image at A, emulsion 2, a-reddish-brown color, a combination of silver and uranium salts. nlm is washed and dried in the' dark.

Referring to Figure 5, the'state of the lm is now as follows: In region B, adjacent to the Isupport I6, is unexposed, usable silver halide emulsion; directly through the transparent support, in region C, emulsion 6, is another deposit of unexposed, usable silver emulsion. Both of these unexposed emulsion regions are directly under positive images already formed; the region B in emulsion 20 is beneath the uranium toned brown image from the magenta printer negative exposure; the emulsion remaining usable in re- .gion' C, emulsion I8, is beneath the already blue toned image formed by light exposure through the blue printer negative.

The next operation is printing from the yellow printer negative to affect the unexposed emulsion regions, to produce a four color positive print, with black as key print, from a tricolorA negative series. Registered exposure is made through front and back of the lm, through the already existing images, so that'latentimages are formed in region B, emulsion 20 and region C, emulsion i8, from the yellow printer negative,

or from the original and a duplicate yellow printer negative, in a simultaneous printing operation lfrom both sides of the positive nlm, in a double-printing contact motion picture printer. Development follows, followed by xing, preferably in acidiiied sodium thiosulfate solution, followed by washing and then by partial drying and notation of the reverse emulsion .I8 Aon a mordanting solution as follows:

Iodine grams-- 6 Potassium iodide rin 50 Water ff i 1,000 Acetic acid, glacial cc-- 10 Auramine grams..- Water The necessary dye will be mordanted by flotation, after short washing, and partial drying by air squeegee, the front of the film, carrying emulsion 20, is floated on a very weak acid solution containing a combination of iodine and po tassium iodide, which is strong enough to stimulate the already existing, but slight mordanting power of the uranium image at region A, emu1. sion 20, without bleaching to any degree the This is followed by washing, partial air drying black silver image inregion B, which isto remain Then the v in its black silver state as a key-print. A solution suitable for this purpose is as follows:

Following this stimulation of the uranium image atA, emulsion20 side of the lm is floated on a basic dye solution as follows:

' Rhodamine grams Water cc-.. 1,000

in which the particles forming the image at A will quickly mordant this magenta dye. Washing follows until the film is clear; either in plain Water, or in a weak solution of sodium thiosulfate, such as 1%, followed by washing before drying. The final film result is a magentauranium image at A, emulsion 20, a black image from yellow printer negative at B, a yellow image from yellow printer negative exposure at region C, emulsion I8, and a blue image at region E.

When ablack, shadow sensation negative is available, it may be printed on the underlying emulsion region B, emulsion 2D, instead of making exposure in that area from yellow printer negative as described in this example.

Example XIII This example is given to illustrate ivnethods which may be used for printing a sound track on positive transparencies in accordance with our invention.

(1) The sound track is printed prior to the iirst development on the blue sideof the positive, developed to its full extent and toned blue to produce a blue sound track in region E or E' of Figures 5 and 6.

(2) The same track is printed prior to first development on the blue' side of the positive, surface developed as in Example IV', leaving a latent undeveloped, underlying image of the sound track corresponding to region D' of Figure 6. The developed portion is toned blue, and the latent, underlying image developed forming a sound track inv a combination of blue and black, preferable for quality of recording to a blue image alone.

(3) The sound trackl is printed entirely in -black. may be accomplished in Example IV, for instance, by interrupting the processing operations following the blue toning, washing, drying, and thereafter printing the sound track upon the nlm in a continuous printer. It will be understood all of these operations take place in the dark. The second development brings out the sound track in black. 'I'his method is applicable to the production of a black sound track regardless of whether an undeveloped, latent image is formed in D' (Fig. 6) in printing the pictorial imag'e.

Example XIV This example is given to illustrate our method of making three-color positive ,transparencieswith a sound track in green. Referring to Figure 6, the sound track negative is printed separately from the pictorial"negatives on. a continuous printer before, after, or simultaneously with the red sensitive negative (blue printer) and the green (or blue-green) sensitive negative (magente. printer). This forms a 'sound track latent image in region lD' and E' (or C', D' and E') of emulsion I8, adjacent the pictorial images as 7l' illustrated in Figures 11 and 12.` Pictorial latent images are formed in emulsion 20, regionvA' and emulsion I8, region E'.

The sound track is surface developed in the first development when the magenta-intended and blue-intended latent images are developed into silver images, and, with the' blue pictorial image, the sound track at E is colored blue.

In the second development the sound track;

without additional printing, develops some more carrying the image downward from surface region E to a lower intermediate` D' region` and sometimes to C region if the printing is strong enough. In any case, only, the surface E is 15 reached by the initia1 blue toning. The lower underlying or buried portion of the sound track in regions D' and E' is developed in the second development into a silver image which in turn, with the treatment of the pictorial images is given an iodiding treatment and becomes a mordant.` When yellow dye Yis applied to emulsion I8, this lower part of the sound track is dyed brilliant yellow, adding yellow to the already formed blue image, thus creating a combination green sound track which is new to the motion picture industry and far superior to any other type or color for fine reproduction of sound sensations. A cross-section of such a film is illustrated by Figure 12 in which region A contains a mordanted magenta image, region B is clear or contains a key image, region C contains a mordanted yellow image, region E contains a blue toned image and the sound track is made up of blue and yellow, which together are visually green. A e

The same general methodcan .be applied in two color photography to form a combination sound track. AFor instance, in Example IV, the sound track buried or intermediate image in 40 region O' or C', D', can be dyed yellow, forming a combined blue and yellow sound track.

Example XV A of emulsion 20(Figure 5) from the magenta printer negative, simultaneously or consecutively with similar exposure of the reverse surface region E, emulsion I8, from the blue printer negative, thus forming latent images on the outer surfaces of the two emulsions upon opposite sides of the Celluloid support I8. Development is carried out in a positive developing solution similar to that used in Example I, followed by short immersion in an acid short-stop bath such as- 1% aqueous solution of glacial acetic acid. This is in turn followed by thorough washing, partial drying by air squeegee and treatment of the rear emulsion by notation on a blue toning solution similar to that used in Example I. This is centration that the surface-region silver yimage at A, emulsion 20, is toned a brilliant reddish colo'r, then the nlm is washed and dried in the dark. r

ReferringtoFlgure5,thestateofthe1mis now as follows: In region B, adjacent to support I6, is unexposed, usable silver halide emulsion. Directly through the transparent support I8 in region C, emulsion Il, is another deposit of unexposed, usable silver emulsion. Both of these regions are directly under positive images already formed. The region B in emulsion 20 is beneath the uranium toned reddish image from the magenta printer exposure negative exposure and the emulsion remaining usable in region C, emulsion I8, is beneath the already toned blue image.

The next operation is duel printing by printing from the yellow printer negatives, through the already formed surface positive images to form images from the yellow printer negatives in the regions B of emulsion 20 and C of emulsion I8. Development follows by which images formed in each of these regions latently by light are reduced to .silver images by the action, preferably, of an amidol type developer. This is followed by fixing and washing. The fixation, preferably of an acidiiied sodium ythiosulfate solution, clears the uranium toning in region A, emulsion 20, to a reddish transparency of nature not further affected by light o`r by a bleach such as one with iodine content, but such a bleach applied only to emulsion 20 does convert the image in region B to a silver` iodide image capable of mordanting a yellow dye. This dye may be applied in known manner to emulsion 20, causing the image in B to be colored yellow without affecting the fixed uranium reddish tone in region A. The printing from the same type of negative into region C has formed there a silver image in black, which may remain unchanged as a key print. Instead of utilizing a yellow printer negative for printing of region C in emulsion I8, a proper black (shadow sensation) key printing negative may be utilized. At this same printing operation, following the first development, uranium and iron toning, washing and dark drying operations, it is highly advisable to print the sound track into emulsion I8, in which both the surface region E and underlying region C are sensitive and receptive-to soundtrack printing.

Thus, in its final state, after carrying out the operations indicated, region A, emulsion 20, consists of a transparent reddish tone from the magenta (red) printer negative, region B, emulsion 20, contains an image in yellow, region C, emulsion I8, contains a key print in black, region E, emulsion I8, contains a blue image, while the sound track, comprising regions E and C of emulsion I8, is in black, because no chemical action affecting aA silver image after development is shown in relation to emulsion I8.

The reddish toned uranium image at surface region A in emulsion 20 may be dye-treated with a magenta dye following the second development but prior to xation of the image created by this development. The uranium image, being mildly mordanting at this stage, will absorb some magenta dye, which will not affect the developed silver image or the remaining unxed silver halide emulsion. Fixation will remove any of the dye temporarily afilxing itself to the unixed emulsion. This magenta dye application by flotation or mechanical means is optional and in any case tends merely to fortify and strengthen the reddish uranium toned image alreadyv formed without in any way aiecting the underlying image in region B, emulsion I8, which, after iodine bleaching treatment, is destined for yel- 'low coloration.

It will be understood thatour invention is subject to some variation in the manner-of its practical application. Various types of positive transparencies prepared in accordance with some printed areas to be colored magenta.

of the examples previously given are illustrated in Figures 7, 8, 9 and 10. These illustrations show the Vuse of our methods in making two color positives with a key image, and three color positives with or'without a key image. It will be understood that the relative arrangement of images may vary in some instances, for example, the yellow image -in Figure 9 may be interchanged positionally with the black key image. the preferred embodiments of the invention is represented by positive transparencies having a yellow image and a blue image in a single emulsion layer on one side of a support and an image in magenta in a single emulsion layer on the other side of the support, with or without a key image. In this way, coloring of the yellow image is not affected by coloring of the magenta image, and vice versa.

For the purpose of the invention, the preferred printing stock illustrated in Figure 3 has an emulsion layer I8 about one and one-half to twice as thick as emulsion layer 20'.

In carrying out the invention, an alternative arrangement may be employed in the bi-pack nlm illustrated in Figure 1. In this alternative arrangement the red lter layer 8,- shown on the first element of the bi-pack may be incorporated as an overlying filter layer on the panchromatic layer of the second element. In either case the red filter dye is a soluble dye, that is to say, a dye which is soluble in an aqueous solution of sodium hydrosuliite or which is water-soluble.

Another modification of the present process involves the use ofa new and improved type of positive stock, as illustrated in Figure 13. This positive stock consists of a Celluloid support or a support made of another transparent inert material carrying a positive emulsion of about twice ordinary thickness which contains a light restraining dye. The dye content should be an exceedingly heavy yellow or orange coloration definitely inhibitingV the passage of light to anything beyond a surface depth. This coloration might also be a deep red, absolutely hindering passage of light rays below the surface.

In printing onI this type of fihn, the following process can be employed. 'I'hrough the support 42 a printing of the blue-'intended positive image from the red recording negative is made. This confines itself to the absolute surface of the thick red impregnated emulsion adjacent the support. 'Ihis latent image is developed in an `ordinary manner leaving unused emulsion in theregions or areas farther from the support. A green recording negative is then employed to print upon these undeveloped regions after removal of the water-soluble light restraining dye. This should be anabnormally heavy printing. The image thus formed from the grcen recording negative is developed, treated with a mordanting agent for basic dyes and then treated successively with yellow and magenta basic dyes. In this successive treatment with unmixed yellow and magenta. basic dyes the type of dye and concentration thereof may be so varied as to cause the lighter printed areas to be colored yellow and the heavier In this way we have found that novel and useful effects can be obtained. A film after coloration is generally illustrated by the showing in Figure 14.

As already indicated, we have discovered that a green sensation recording negative such as may be obtained, for example, from the front element of a bi-pack like that described in Figure 1, when printed in a. normal manner, produces a positive One ofcorrect for magenta coloration, but when abnormally heavy printed produces a positive which is incorrect for magenta printing, `inasmuch as the areas representing yellow and mixed coloration containing yellow, suchA as green, are not left-clear.

To facilitate the printing of the abnormally heavy positive from the green recording nega-' that is, correct for magenta coloration. This we Then, we make an abwill term po'sitive M. normally heavy printed positive from the same green recording negative. This we wil1 call positive Y. Abnormally heavy positive printing, particularly in motion picture work, is inconvenientand therefore, a duplicate negative for actual production is desirable. This We produce by making a duplicate negative, by known methods, of the positive Y which is the abnormally heavy printed positive. In making the duplicate negative We prefer to interpose the normal positive M between the positive Y being copied and the new negative material on which the copy is being made. However, direct copying of the positive Y onto the new negative material may be satisfactorily utilized in our processing steps. Such interposition is of course understood to be in exact registry.l

One of the features of our invention resides in the discovery that a uranium toning treatment of a silver image, in conjunction with an iodiding treatment, produces a much stronger mordant 'than the use of either treatment alone.

Among the basic dyes which we have found to bev particularly suitable for our invention are: Rhodamine and Fuchsine for coloring in magenta, and auramine and thioavine for coloring in yellow. It will be understood, however, that other dyes maybe used.

Among other things, we have found that'toning in a uranium toning solution of not too great strength, sufficient to provide a light brown tone but not continuing yuntil a deep reddish-brown tone is obtained, followed byv treatment of the image in a solution comprising mainly iodine, po-

tassium iodide and a mild acid, results not only in a strong mordant for basic dyes, but a governable and controllable brown tone which adds strength and definition to the finished color print.

The advantages of our invention will readily be apparent. We are able to produce any number of positive transparencies from a set of negatives. Our invention' is clearly distinguished, therefore, from those reversal methods by which negatives exposed photographically are transformed into positives in color, thus limiting the scope of production to only one original print in color.. It should also be noted that our methods do not depend upon the time element, relative density, or specic gravity of solutions in reaching selectively different strata of emulsions. Each i o1' the processing -steps in our method provides results dependent upon direct chemical action,

.with obvious advantages in the production of prints in such quantity as to'be valuable for commercial usage, particularly in the motion picture neld, which requires several hundred prints simplicity and economy.

tion of three or more color values in a single positive transparency, with or without a key print in brown or black representing one of said color values, and is not to be confused with ordinary two color photography. Furthermore, it is to be noted that we completely avoid imbibition from matrices, which now forms the basis for known commercial methods of three and four color photography. Matrix machinery of the character now used is costly` and complicated. In other respects, particularly with regard to the type of lm employed, our methods provide outstanding vdifferent printing values, as, for example, positives containing two color images and a black key image, or three color images, or three color `'images and a key image. The expression uraimages.

of an averagelm to supply the demand of motion picture theatres. Y Our linvention is concerned with the producnium toning is employed herein to describe the use of solution of uranium salts yin treating silver The term iodiding or iodiding treatment is employed to describe a treatment of silver images with solutions containing or consisting essentially of iodine and salts thereof adapted to convert silver images to silver iodide derivatives. By a combined uranium toning and iodiding treatment we mean a treatment with afuranium toning solution and an iodiding solution simultaneously or successively.

Having thus described the invention, what we claimA as new and desire to secure by Letters Patent of the United States is. I

1. In a method of positive printing in color photography, the steps which comprise forming two latent images of diiferent color printing values on opposite sides of a transparent support having only one color blind emulsion layer on each side thereof by the action of light penetrating two negatives of different color recording values, one of them recording red sensations, developing the latent images Without fixation to form metallic silver images, coloring the image printed from the red sensation negative in its appropriate color value by iron blue toning on one sideA of said support only, fixing out the image bearingemulsion on the opposite side of the support; forming another latent image of still' different printing value in the still light sensitive portion of the emulsion underlying the formed cyan blue image by the action of light penetrating a color value recording negative, a formed uncolored image and the support; developing said latent image and ilxing out said emulsion to form a silver metallicuncolored image; coloring hitherto uncolored images according to the appropriate color printing values subtractively complementary to the negatives employed in forming said images by means of successively impregnating said images with mordanting solutions and solutions containing basic dyes, producing in two positive emulsion layers three color images each with a plane base.

2. A method of positive printing in color photography which comprises providing color sepadifferent printing ration negatives .representing selective sensitivities of three differing regions of the spectrum; providing commercial color blind positive double coated motion picture film impregnated with restraining yellow dye identical in the emulsions on both sides of a transparent support; providing ordinary photographic developing solution;

lproviding an amidol type photographic solution vfor second developing operation; providing a solution for cyan-blue toning of silver images;

' providing a solution capable ofv rendering silver images receptive to basic dye mordanting coincidentally forming a brownish key image;vproviding a solutioncontaining a basic magneta dye; providing another solution containing a basic yellow dye; providing a solution containing sodium thiosulphate for iixing out image containing emulsions; forming two latent images of different color printing values on opposite sides of a transparent support having only one emulsion layer on each side thereof by the actionof light penetrating negatives of differing color components, developing both of said images to silver images, then cyan-blue chemically toning one of said images in its appropriate color value on one side of said support only leaving the developed image on the one side of the support uncolored fixing out the emulsion containing the said uncoloredimage; printing through the said uncolored'image and the support to form va latent image in the still unused light sensitive emulsion underlying the said surface cyan blue chemically toned image by the action of light penetrating an hitherto unprinted negative of the said separation series; developing said latent image. with said amidol type solution; fixing out the emulsion bearing the silver image thus formed; coloring in subtractive complementary colors the hitherto uncolored images by impregnation with the said mordanting solution and the said separate basic dye solutions.

3. A method of positive printing in color photography which comprises providing a first color separation negative substantially green `recording; providing a second negative substantially blue recording formed by special gamma copying from the said first negative; providing a third negative substantially red recording; providing unexposed motion picture iilm of color blind characteristics, the emulsions coated upon each outer surfaces of the emulsion layers leaving sensitive emulsion regions between the support and the developed images, xing out said sensitive emulsion on the obverse side of said positive film; chemically toning the reverse side of said positive lrn; printing from said second negative through the uncolored image on the obverse side of the said positive iilm and through the support thereof to form a latent image in the still light sensitive emulsionadjacent to the said support on the reverse side of the saidY lm to form a latent image; developing the said latent image with the said acid developer; fixing and washing the silver metallic image thus formed;

impregnating the uncolored silver metallic images on both sides of the said positive iilm with said mordanting solution; impregnating the image on the obverse side with said magenta dye solution; impregnating the reverse side with the said yellow dye solution.

4. A method of positive printing in color photography which comprises providing as a rst negative a substantially green yet blueI sensation containing color separation negative; providing side of a transparent support being identical in composition; providing a known. standard alkaline developing solution for the rst developing l operation; providing a known .acid developing solution for the second developing operation;

providing a known mordanting solution capable plementary coloring the image derived from the third negative; forming a latent image onvthe obverse side by printing from said first negative and forming a latent image on the reverse side by printing from said third negative by the action of light interruptedby said negatives and effecting said positive lm; developing said latent images in said alkaline developer in such manner. that silver metallic images are formed near the as a secondnegative a special gamma copy of said iirst negative to act as a blue record representing separation; providing as a third'nega.- tive a color separation substantially recording red selective sensitivities; providing unexposed positive motion picture iilm consisting of emulsions of identical color blind photographic characteristics coated on each side of a transparent support; providing known photographic chemical solutions including an alkaline type developer, an acid type ldeveloper, a fixing bath, a cyan-blue toning solution, known stop baths, known clearing baths; providing a solution for mordant-toning containing uranium nitrate; providing another solution for mordant-toning containing uranium nitrate and iodine in the presence .of potassium iodide and potassium ferricyanide; providing a solution containing a basic magenta dye suitable for coloring the image derived from thesaid first negative; providing a solution containing a basic yellow dye suitable for coloring the image derived from the said second negative; providing suitable apparatus for the operations of printing, developing, fixation, washing and drying in darkness, toning, mordanting and dye forming and said ldeveloping being effected under such conditions as to leave sensitive emulsions in the regions between the `support and the developed silver metallic images occupying the outer plane surface regions of the emulsions coated on each side of the said support; impregnating the emulsion on the reverse side of the said support with the said cyan blue toning solution thus forming a cyan-blue image on the surface of said emulsion but leaving sensitive emulsion `underlying said image adjacent to the said support; xing out the emulsion on the obverse side of the lsaid support thus forming thereon an uncolored developed image; then printing through said developed image from the said second negative of v vof the support, underlying the formed cyan-blue image; developing said latent image in said acid developer; impregnating the uncolored image on the obverse side of the support successively with vthe said two mordant toning solutions and the said magenta dye solution; impregnating the reverse side of -the support bearing the cyan blue toned image and the uncolored image with one of said mordant toning solutions; further impregnating said reverse side with the said yellow dye solution; the transparency thus formed being colored in the colors subtractively complementary to the color values represented by the negatives employed in printing the individual images comprising said three color positive print with brownish key-tone. l

5. A method of color photography which comprises photographing an object on a bi-paek negative material under conditions effectively recording green on the front element of said bi-pack and red on the rear element, developing and xing said negatives, preparing a lighter gamma duplicate of the green sensation negative, printing latent images from said red sensation negative and from the denser green sensation negative on opposite sides of positive printing stock containing only one emulsion on each side of a transparent support, developing said images, said printing and developing being such as to form images in the outer surface regions of said emulsions leaving a sensitive undeveloped region adjacent the supvtography adapted to form three images of diiferent color values in two emulsion layers of positive printing stock arranged upon opposite sides of a' transparent support' which comprises providing a first color separation of blue to green sensitivity so yellow filtered in the taking operation as to be substantially green sensation recording; providing a second negative of substantially red selective sensitivity recording value; providing unexposed positive motion picture iilm consisting of emulsions of identical color blind photographic characteristics coated on each side of a transparent support; providing known photographic chemical solutions including an alkaline type developer, an acid type developer, a fixing bath, known stop baths and known clearing baths; providing a mordanting solution capable of rendering silver metallic images receptive to basic dye mordantingoperations; providing a solution containing a basic magenta dye suitable for coloring the first image printed from said first negative; providing a cyan-'blue toning solution suitable for coloring the image printed from the said second negative; providing a solution containing a basic yellow dye suitable for coloring the second image printedA from the first negative, in substituting representation of blue record image; providing suitable equipment for the differential processing of opposite sides of said positive motion picture film printing from the said first bluegreen negative onto the obverse side of said printing stock to form a latent image therein adapted for coloring in magenta, printing from the said second red sensation recording negative on the sensation negative blue, then printing through r the uncolored image from the lighter gamma duplicate of the green sensation negative to form a latent image in an underlying emulsion, de-

veloping and coloring the uncolored image in the outer region of the emulsion magenta, and the image in the region adjacent the support yellow.

6. A method of positive printing in quadricolor photography adapted to form four images of different printing values in two emulsion layers of positive printing stock arranged on opposite sides of a transparent support which comprises printing fr a green sensation recording negative on the obverse side of said printing stock to lform a latent image therein adapted for coloring in magenta, printing from a red sensation recording negative on the reverse side of said printing stock to form a latent image therein adapted for coloring in blue, developing said images by a development leaving a portion of the image on the re-v y verse side nearer the support as an undeveloped latent image, toning, the developed image on said reverse side blue, printing through a lighter gamma duplicate of the green sensation recording negative through the developed uncolored image on the obverse side to form a latent image nearer the support on the obverse side, developing the latent image on the reverse'side, and the latent image on theobverse side, coloring the image nearer the support on the obverse side yellow and the surface image on the obverse magenta, thereby -forming a positive print having blue in the surface region of the image on the reverse side, a black key image nearer the support on the ^reverse',`side, a, vyellow imagevnearer the support on the obverse side, and a magenta image nearer .the surface on the obverse side.

l'7. A method of positive printing in color phoreverse side of said printing stock to form a latent image adapted for coloring in blue, developing said images, said image on the reverse side being developed by a development leaving a portionpof the emulsionvnear the support unexposed and still sensitive, blue toning the image on the reverse side without ailecting the image on the .obverse side; drying in darkness'to prepare for another printing operation, forming a latent image on the reverse side adjacent the support by printing from said first negative by greatly increased printing light diminishing thus the effective gamma of said negative in substitution for a blue record negative through the support and the developed image on the obverse side, then developing the latent image on the reverse side between the blue toned image and the support, coloring said developed image yellow and colo'ring the image on the obverse side magenta by successive impregnation with said mordanting solutions and said dye solutions.

8. A method of positive printing in color photography which comprises the following steps; simultaneously printing in register from two different color separation negatives of a tricolor separation set to ,opposite sides of a double coated positive film; one printing being through the green sensation recording negative to form a latent image on the' outer plane surface of the obverse side and the other printing being through the red sensation recording negative to form a latent image on the outer plane surface of the reverse side; developing said latentimages without fixation; cyan-blue toning the image on the f outer plane surface of reverse side of film; xing out the obverse side of film; drying the hn `in darkness; printing in imageregistry from the blue sensation recording negative of said tricolor separation set through the obverse side of film and the image already printed thereon from green sensation recording negative, through the transparent support and by such penetrating action of light forming a latent image adjacent the support and with its plane surface as a base on the reverse side of said film underlying the blue` image; developing said latent image; converting the silver images on the obverse and the reverse sides of thel said film to images capable of basic l' dye mordanting; `coloring the image on the obverse side magenta and coloring the image lying immediately adjacent to the support on the reverse side yellow, by applications of basic dyes of appropriate color.

9. A method in color photography which com- Y prises the following steps; providing acolor separation negative series consisting of three members, the first, a blue-green sensation recording resulting from the ordinary exposure of a front bi-pack element to an object; the second, a bluegreen sensation recording resulting from a yellow filtered exposure of a front bi-pack element to'an object; the third, a red sensation recording resulting from the exposure of a rear bi-pack element'to an object; providing unexposed double coated color blind positive motion picture lm: simultaneously printing in register from the said red sensation negative to the reverse side of the said positive film and from the said rst negative to the obverse side thereof to form latent images; developing the said latent images without fixation; said developing producing silver metallic images in the outer plane surface regions leaving underlying light sensitive emulsion adjacent to the support fixing out the obverse side of the said lm, cyan blue toning the reverse side of the said film Washing, and drying the said film in darkness; printing in register from the said second negative through the obverse side of the iilm and the uncolored image thereon to form by the penetration of light through the transparent support a latent image in .the still sensitive emulsion underlying the cyan-blue image on the reverse side of the film; developing thel said latent image and coloring it magenta; coloring the image on the` obverse side of the film yellow such coloration being effected by impregnating the silver` metallic images hitherto uncolored with a solution capable of rendering said images receptive to basic dye mordanting and then impregnating each' of the said images with a solution containing a basic dye of the said indicated colors subtractively complementary to the color value represented by the negative from which each of the said images was printed, thus vforming three color images each with a plane base in two positive emulsions completing a transparency for projection.

10. A method of color photography which comprises photographing an object on a bi-pack negative material under conditions effectively recording green on the front element of the bi-pack and red on the rear element, developing and fixing said negatives, preparing a lighter gamma duplicate of the green sensation negative, printing latent images from said red sensation negative and from the denser green sensation nega- -tive on opposite sides of positive printing stock containing only one emulsion on each side of a vtransparent support, the green sensation negative being printed to the obverse side and the red sensation negative to the reverse side of said positive printing stock; developing said latent images, said printing and developing being such as to form metallic silver images starting at the outer plane surfaces of said positive emulsions leaving a sensitive undeveloped region adjacent the support, coloring the image printed from the red sensation negative blue, then printing through the uncolored image on the obverse side of positive film from the lighter gamma duplicate of the green sensation negative to forma latent image, through the support, in the emulsion underlying the blue image, developing and coloring the uncolored image on the obverse side of saidlm magenta and the image in the region adjacent the support on reverse side of said lm yellow.

11. A process in color photography which comf prises the following steps; providing unexposed color sensitive negative motion picture film capable of ldifferentially recording green, blue and red selective sensitivities; providing unexposed commercial positive motion picture lm coated with color blind emulsion layers on both sides of a transparent support; providing a standard solution for motion picture lm developement; proviling a solution for film development containing amidol; providing a xation solution containthe said unexposed positive lm by thev action of light penetrating the saidv green sensation negative to form a latent positive image thereon; printing to the reverse side of the said positive film by the action of light penetrating the said red record negative to form a latent image thereon; impregnating the said positive lm with-the said standard* developing solution to form metallic silver images adjacent to the plane outer surfaces on the said positive lil-m, leaving unused lightl sensitive emulsions underlying said images adjacent to the support on both sides; impregnating the reverse side of the said positive film with said cyan-blue toning solution to convert the surface silver image to a blue toned image; fixing out the observe side without affecting the still sensitive emulsion underlying the cyan blue image on the reverse side of the support; washing and drying the film in darkness; printing to the observe side of said positive iilrn by the action of light intercepted by the said blue record negative through the already formed green value metallic silver image and the transparent support to form a latent image in the light sensitive emulsion adjacent to the support `on the reverse side of the film underlying the cyan blue toned image from the red record negative printing; developing the said latent image with the said amidpl developing solution to form a silver image; impregnating the said positive lm with the said mordanting solution, thus rendering the silver images on each side of vthe support receptive to basic dye mordanting; impregnating the obverse side" ofthe said positive lm with the said magenta -dye solution thus coloring the green color value image in its subtractive complementary color; impregnat- -ing the reverse side of said positive film with the said yellow dye solution, thus coloring the blue color value image in the color subtractively complementary thereto.

12. A process in color photography which includes the following steps; providing unexposed bi-pack motion picture nlm sensitive on the front element to green and blue but not to red and sensitive on the rear element to red but not to green or blue; providing unexposed commercial positive motion picture film coated with color blind emul- -sion layers on both sides of a transparent supsolution containing a basic magenta dye; providing a coloration solution containing a basic yellow dye; providing a camera to expose said color sensitive negative nlm; providing a sandwich type cinematographic nlm printer capable of simultaneous printing of two color records onto a double coated positive nlm; exposing said color sensitive nlm to an object interposing a yellow nlter material to render the front element sensitive to green; developing, nxing and drying said exposed color sensitive nlm to produce negative color ima-ges differentially recording green and red records; producing by known copying methods a special gamma duplicate negative of-said green record; printing to the obverse side of said unexposed positive nlm by the action of light .penetrating said original green record negative to form a latent positive image thereon, simultaneously printing to the reverse side of said positive nlm by the action of light penetrating the said red record negative to form a latent image thereon; impregnating the said positive nlm with the said standard developing solution to form metallic silver images adjacent to theplane outer surfaces on the said positive nlm, leaving unused light sensitive emulsions underlying the said images adjacent to the support on both sides; impregnating the reverse side of the said positive nlm with the said cyan-blue toning solution to convert the surface silver image into a blue toned image; nxing out the obverse side without anecting the still light sensitive emulsion underlying the cyan blue image on the reverse side of the support; washing and drying the nlm in darkness; printing to the qbverse side of the said positive nlm by the action of light intercepted by the said special gamma duplicate green record negative through the already formed green value metallic silver image and the transparent support to form a latent image in the light sensitive emulsion adjacent to the support on the reverse side of the support underlying thel cyan blue toned image from the red record negative printing; developing the said latent image with the said amidol delveloping solution to form a silver image; impregnating said positive nlm with said nxing solution and washing; impregnating the said positive nlm with the said `mordanting solution, thus rendering the silver images on each side of the support receptive to basic dye mordanting; impregnating the obverse side of the said positive nlm with the said magenta coloration solution'.

and the reverse sidev with the said yellow coloration solution thus coloring the green value image in its proper subtractive complementary color and the special gamma green record substituting for asses-19 blue record in color subtractively complementary to bluevalue, producing a final transparency in magenta,- yellow and blue coloration in`two color blind positive emulsions.

13. A process in color photography which includes the following steps; providing unexposed bi-pack motion picture nlm sensitive on the front element to green and blue but not to red andv sensitive on the rear element to red b ut not to green or blue; providing unexposed commercial positive motion picture nlm coated with color blind emulsion layers on both sldes'of a transparent support; providing a standard solution for motion picture nlm developement; providing a, solution for nlm developement containing amidol; providing a solution for nxation containing sodium thiosulphate; providing a-cyan-blue toning solution capable of converting metallic silver images to an iron blue color tone; providing'a solution for bleach mordanting containing iodine,

potassium iodide and potassium ferricyanide; providing a coloration solutioncontaining a basic magenta dye; providing a coloration solution conon the front element, the red recording being.

situated on the rear element, said recordings resulting in the v formation of latent images on said color sensitive nlm; developing said latent images to form negative silver images; nxing, washing and dryingsaid negative nlm to produce negative color images differentially recording green, blue and red records; printing to the obverse side of said unexposed positive nlm by the action of light penetrating said green record negative .to form a positive` latent image thereon, simultaneously printing to` the reverse side of said positive nlm by the action of light penetrating the said red record negative to form a latent image thereon; impregnating the said positive nlm with the said standard developing solution to form metallic silver images adjacent to the plane outer surfaces on the said positive nlm,

,l leaving unused light sens'itive emulsions underly- 'Y ing the said images adjacent to the support on both sides; impregnating the reverse side of the said positive nlm with the said cyan blue toning solution to convert the surface silver image into a' blue tonedvimage; nxing out the obverse side by impregnation with said-nxing solution without yaffecting the still light sensitive emulsion underlying the cyan blue image on the reverse side of the support; washing and drying the nlm in darkness; printing to the obverse side of said positive nlm by the action of light intercepted by the said blue record negative through the a1- ready formed green value metallic silver image and the Ytransparent support to form a latentimpregnating the reverse side of the film with tion and washing; impregnating both sides of the said positive film with the said mordanting solution, thus rendering the silver images on both sides of the support receptive to basic dye mordanting operations; impregnating the obverse side of the said positive film with the said magenta coloration solution thus coloring the green color value image in its proper subtractive complementary color; impregnating the reverse side of the said positive iilm with the said yellow coloration solution, thus coloring the blue record image inthe color subtractlvely complementary thereto and forming three completed color images all in their subtractively complementary colors in the two emulsions on opposite sides of said positive nlm producing a transparency suitable for motion picture projection.

14. A process in color photography which includes the following steps; providing motion picture light sensitive film unexposed, said film being of color selective type providing commercial double coated color blind positive film unexposed;

providing a solution for lm development containing metol and hydroquinone; providing a solution for iilm development containing amidol; providing a solution for film fixation containing sodium thiosulphate; providing a solution for cyan-blue toning of metallic silver images; providing a mordanting solution containing iodine, potassium iodide and potassium ferricyanide; providing a solution containing a basic magenta dye; providing a solution containing a basic yellow dye; providing a camera to expose said color selective film; providing cinematographic printing apparatus to print from a color selective record onto double coated positive film; exposing saidselective film to an object to form multiple latent color records; developing said latent color records to form metallic negative images; fixing and washing said images and drying to form printing negatives; providing means for the identification of red record;v green record and blue record selective sensitivity recordings making up the set of printing negatives; exposing from a green record negative to the outer plane yellow solution, thus coloring the blue record positive image in color .complementary to its own sensitivity value without affecting the already formed cyan-blue toning coloration of the red record image on the surface region of the reverse side.

15. A method of color photography which comprises photographing an object on a bi-pack negative material effectively recording blue to green on the front element of said loi-pack Ain surface on the obverse side of said positive film to form a latent image on the outer surface region; exposing from a red record negative to the outer plane surface on the reverse side of said positive nlm to forma latent image on the outer surface region; developing said latent images to form silver images. in the surface regions of the emulsions on both sides of the support; washing the film Without fixation; cyanblue toning the silver image on the reverse side of the support leaving emulsion underlying said image adjacent to the support still light sensitive; washing the film and fixing out the image containing emulsion on the obverse side; washing and drying the film in darkness; printing from the blue record negative by 4printing light through the already formed silver image on obverse side and through the support to form a latent image in the light sensitive emulsion adjacent to the support and underlying the formed cyan-blue image; developing the latent image thus formed by impregnating with solution containing amidol, following this operation by fixing and washing;

differing gammas on different surface" areas thereof and red on the rear element in differing gammas on differing surfaces thereof; preparing duplicates of the original varied gamma area negatives capable of direct contact printing. in cinematography, the duplicate negative in heavier gamma being designated the iii-st negative for the production of final positive image colorable in magenta; the duplicate negative in lighter gamma being designated the second negative for the production o f final positive image colorable in yellow; the duplicate negative from area of the red record being designated the third negative for the production of final positive image colorable in blue; printing latent images from said red sensation negative and from the denser heavier vgamma green sensation negative on opposite sides of'positive printing stock containing only one emulsion on each side of a transparent support, the green sensation negative being printed to the obverse side and the red sensation negative to the reverse side of said positive printing stock, developing said latent images,` said printing and developing being such as to form metallic silver images starting at4 the outer plane surfaces of said positive emulsions g leaving a sensitive undeveloped region adjacent the support, coloring the image printed from the red sensation negative blue, then printing through the uncolored image on the obverse side of positive nlm from the lighter gamma duplicate of the front element negative to form a latent image, through the support, in the emulsion un-v derlying the blue image, developing and coloring the uncolored image on the obverse side of the film magenta and the image in the region adjacent the support on reverse side of said film yellow.

16. A process in color photography which includes the following steps; providing unexposed commercial positive motion picture film coated with color blind emulsion on each side of a transparent support; providing color separation nega: tives representing green, blue and red selective sensitivities; providing a known solution for motion picture positive film development; providing ,another known solution for positive film .development containing amidol; providing a known xationsolution; providing a known cyan-blue toning solution; providing a known uranium nitrate toning solution; providing a mordanting solution containing iodine, potassium iodine and potassium ferricyanide; providing a coloration solution containing a basic magenta dye; providing another coloration solution containing a impregnating the entire lm with mordanting solution, thus rendering the silver images on each side of the support receptive to basic dye mordanting; impregnating the obverse sidek of the film with magenta solution, thus coloring the green positive record thereon in color subtractively complementary to its own sensitivity value;

registering.

thereon; impregnating the said positive film with the said developing solution to form metallic silver images adjacent tothe plane outer surfaces on the said positive nlm; leaving unused light sensitive emulsions underlying said images adjacent to the support on both sides; impregnating the reverse side 'of the said positive film with said cyan blue toning solution to convert the surface image now metallic silver, to an iron blue toned image; fixing out the obverse side of the' said positive film without affecting the still light sensitive emulsion underlying the formed blue `toned image on the reverse side of the support;

bythe action of light intercepted by the said washing and drying the lm in darkness; printing to the obverse side of the said positive film blue record negative through the already formed metallic silver image of green color value and the transparent support to form a latent image in the light sensitive emulsion adjacent to the magenta dye coloration solution and the reverse side with the said yellow dye coloration solution; washing to clear the highlights and thus forming a positive projectionable transparency representing the subtractive. complementary colors of the original color records with an added key co1- oration in brown.

EDWIN BOWER HESSER. EVA LOUISE V. HESSER. 

